Intellectual and Physical Disability and Risk of COVID-19 Infection, Hospitalisation, and Mortality: A National Cohort of 3.7 Million Adults in Scotland

BACKGROUND: Disabled people experienced disproportionately poor outcomes during the COVID-19 pandemic, but evidence remains uneven across disability status and across stages of the disease pathway. Few population-wide studies have simultaneously examined infection, hospitalisation, and mortality while distinguishing intellectual disability from physical disability. The aim of this study was to quantify associations between disability status and COVID-19 outcomes in a national Scottish cohort. METHODS: This population-wide retrospective cohort study included 3,719,651 adults aged ≥ 16 years alive and resident in Scotland on 1 March 2020. Disability status was derived from the 2011 Scottish Census and categorised as intellectual disability (n = 17,354), physical disability (n = 377,706), or no recorded intellectual or physical disability (comparison group; n = 3,324,591). Participants were followed from 1 March 2020 until 30 April 2022 for first laboratory-confirmed SARS-CoV-2 infection, first COVID-19 hospitalisation, and COVID-19-related mortality. Associations were estimated using Cox proportional hazards models with sequential adjustment for demographic factors, socioeconomic factors, health-related factors, and COVID-19 vaccination status. RESULTS: During follow-up, 306,343 participants had a first recorded SARS-CoV-2 infection, 22,945 experienced a first COVID-19 hospitalisation, and 12,893 died from COVID-19-related causes. Crude incidence rates for first recorded SARS-CoV-2 infection were highest among adults with intellectual disability, whereas crude incidence rates for COVID-19 hospitalisation and mortality were highest among adults with physical disability. In fully adjusted models, compared with adults with no recorded intellectual or physical disability, intellectual disability was associated with higher hazards of infection (HR 2.65, 95% CI 2.57-2.73), hospitalisation (HR 1.60, 95% CI 1.40-1.83), and mortality (HR 1.58, 95% CI 1.30-1.91). Physical disability was also associated with higher hazards of infection (HR 1.60, 95% CI 1.58-1.62), hospitalisation (HR 1.16, 95% CI 1.12-1.19), and mortality (HR 1.23, 95% CI 1.19-1.28). Across all three outcomes, hazards were higher for intellectual than physical disability. CONCLUSIONS: Both intellectual and physical disability were independently associated with increased risk across the COVID-19 disease pathway, with stronger associations observed for intellectual disability. These findings support disability-inclusive pandemic preparedness and prevention strategies that recognise heterogeneity of risk within the disabled population and promote equitable access to timely care.